How To Reset A Vaillant Boiler – A Heating Engineer’s Guide

During extremely chilly weather when your boiler is working super hard, it may run into a glitch or two. Sometimes, your boiler just needs a little nudge to get back on track and continue keeping you nice and warm. You might need to push the reset button to encourage your boiler to start afresh after a minor technical hitch occurs, such as a drop in water pressure, or a safety feature kicking in.

The good news is that it is one of the few jobs that a homeowner can do themselves without calling out a heating engineer. So knowing where your reset button is and how to reset it safely could keep you from being without heat and hot water when you need it most!

If you are the owner of a Vaillant boiler and need to find out how to reset it safely as well as common causes for your boiler to shut down, read on.

When Can I Safely Reset My Vaillant Boiler?

Safety is paramount. If you detect a gas smell or have any safety concerns related to your boiler, evacuate your property straight away and dial 0800 111 99 for emergency gas services. Gas issues can be extremely dangerous and may lead to explosions.

It is important to highlight that resetting your Vaillant boiler won’t fix any underlying issues that are causing it to fault. If you are unsure about tackling the root cause yourself, always enlist the help of a qualified engineer.

There will be instances where resetting is appropriate. For example, low or high-water pressure or boiler leaks are common reasons for resetting. Also, if the boiler detects a fault, it will lock itself down as a safety precaution to prevent damage to your central heating system. If your boiler is in lockout mode, a reset will get things up and running again.

If you notice an error code, such as a F28 fault code, consult your boiler’s manual for guidance. Error codes can vary slightly, and while some are homeowner friendly, many require a professional heating engineer for resolution.

A Quick And Easy Guide To Resetting a Vaillant Boiler

1. Ensure you have resolved the cause of the lockdown

Before attempting to reset your boiler, make sure you have resolved the cause by checking the boiler error code on the display screen and referring to your instruction manual to learn what issue the code symbolises. Aside from minor fixes such as defrosting your condensate pipe or topping up the pressure, we recommend all errors should be examined by a Gas Safe Registered (GSR) engineer like the team at Happy Dog Plumbing. Only when the heating engineer is satisfied the issue has been resolved should you move onto the following steps:

2. Locate the reset button

The most common place to find it is on the display screen and will show as a flame with a line crossed through it, however some boilers may use a reset dial rather than a button. The best way to be certain is to check your Vaillant boiler manual as it can vary depending on the specific model you have.

3. Press and hold the reset button for 3-5 seconds

to ensure the boiler correctly resets and the display screen changes.

4. Check that the ignition flame is illuminated.

You may be able to hear the boiler working. The error code should not be showing anymore.

5. Test the boiler is working as it should.

Wait ten minutes and run a hot water tap to see if hot water is flowing through your system. Or turn up the temperature and see if the system responds.

What Should I Do If The Boiler Won’t Reset?

If your Vaillant boiler takes a few minutes to reset, be patient and allow enough time for it to shut down and restart. If it doesn’t restart and you see an error code on the digital display, it’s time to call a Gas Safe Registered heating engineer.

Keep in mind that even if you manage to reset your boiler and it starts working again, repeated shutdowns could signal an ongoing issue. In such cases, it’s best to reach out to a professional boiler engineer for assistance.

Common Reasons You Might Need To Reset Your Vaillant Boiler

If your boiler keeps locking out frequently, there might be an underlying problem. Simply resetting your boiler won’t solve the issue, so it’s a clever idea to dig a little deeper to understand what’s going on. Don’t worry; we’ll guide you through the main reasons boilers often shut down.

Low Water Pressure

If your Vaillant boiler’s water pressure drops below 1.5 bar on the pressure gauge, it’s considered too low and you might encounter issues. You can try resolving this by repressurising your boiler following the instructions in the manual. However, if you identify a leak, it’s best to contact a Gas Safe Registered engineer for assistance. Low water pressure can make your boiler work harder, leading to shutdowns and error codes on the digital display. If you’re dealing with the F22 fault, consult our F22 fault guide for troubleshooting. If the problem persists, reach out to a Vaillant-trained boiler engineer for further assistance.

High Water Pressure

As with low water pressure, high pressure will also force your boiler to lock down. If your pressure gauge is consistently shooting higher than 2.5 bar, your water pressure is too high. Sometimes a quick bleed of your radiators will solve the issue but if it doesn’t, you’ll need to call in a GSR professional.

Boiler Overheating

If there are blockages in the system or the pump isn’t working properly it can cause the water temperature to rise and overheat the boiler. As a safety measure, the boiler will shut down on its own. But it’s a bit tricky to fix on your own. It’s best to leave it to the experts, so make sure to reach out to a qualified professional to take care of these issues. Your safety is important, and they’ll know just what to do!

Boiler Leaks

Leaks can be a bit of a headache when it comes to your boiler. The tricky part is that fixing the boiler and handling any water damage can get a bit pricey. So, catching it early is the secret to avoiding those hefty repair bills.

The moment you spot even a tiny leak, don’t hesitate – give a shout to a central heating expert. They’ll track down the source and sort it out, saving you from potentially bigger troubles down the line.

Ignition Failure Or Gas Supply

If your boiler decides to go on a little break, it might be due to a hiccup in the gas supply or a little ignition glitch. The usual suspects causing this might be some blockages in the flue, a bit of trouble with the gas valve, or an issue with the ignition lead. But hold off on hitting that reset button – you’ll want a GSR engineer to swing by and check things out first. They’ll give it a once-over and make sure everything’s in tip-top shape before your boiler gets back to keeping your home nice and cosy.

The best way to prevent boiler breakdowns and regular restarts is to have your boiler serviced annually. Put it on your calendar like you would a car MOT or service and you won’t regret it in the long run. Your GSR heating engineer will test your central heating system to check everything is working as efficiently as possible and will recognise potential faults before they escalate. You’ll avoid having to fork out for emergency repairs or a possibly even a whole new boiler, and you’ll be contributing more positively to the environment.


Book in your annual boiler service with us today and join the thousands of other happy customers that have benefitted from our expertise.